1. Field of the Invention
This invention relates to a suspension comprising a flexure with conductors and used in a disk drive for an information processing apparatus, such as a personal computer.
2. Description of the Related Art
A hard disk drive (HDD) is used in an information processing apparatus, such as a personal computer. The hard disk drive comprises a magnetic disk rotatable about a spindle, a carriage turnable about a pivot, etc. A suspension is mounted on an arm of the carriage. Examples of the suspension are disclosed in Jpn. Pat. Appln. KOKAI Publication No. 9-282624 (Patent Document 1) and U.S. Pat. No. 6,754,045 (Patent Document 2). The suspension comprises a load beam, a flexure superposed on the load beam, etc. A gimbal portion is formed near the distal end of the flexure, and a slider is mounted on the gimbal portion. The slider is provided with elements (transducers) for accessing data, that is, for reading or writing data.
Flexures of various forms have been put to practical use according to required specifications. A flexure with conductors is a known example, which comprises a metal base formed of a thin stainless-steel sheet, electrically insulating layer formed on the metal base, conductive members, etc. The insulating layer is formed of an electrically insulating material, such as polyimide. The conductive members are formed of copper and arranged on the insulating layer. One end of each conductive member is electrically connected to an element (e.g., an MR element) of the slider, and the other end to an electrical circuit, such as an amplifier.
The conductive members are disposed parallel to the metal base with the electrically insulating layer therebetween. An eddy-current loss is caused if a high-frequency current is passed through the conductive members. This eddy-current loss is influenced by the metal base. A flexure with conductors whose metal base is not formed with apertures, for example, is subject to a substantial eddy-current loss. Since the loss in a high-frequency band is particularly great, in this case, it is disadvantageous to high-speed data transmission. In the flexure disclosed in Patent Document 1, a plurality of apertures are formed at regular intervals in the longitudinal direction of the metal base. These apertures can reduce the eddy-current loss at a conductive circuit portion.
The rear part (so-called flexure tail portion) of the flexure with conductors extends from the rear end of the load beam toward the carriage. Therefore, the flexure tail portion is liable to sway. In order to suppress the sway of the flexure tail portion, in an actuator assembly of Patent Document 2, a slit is formed in the carriage, and the flexure tail portion is inserted into the slit.
In the flexure with a large number of apertures in the metal base, as described in Patent Document 1, the eddy-current loss at the conductive circuit portion can be reduced in comparison with the case of the flexure without apertures. If the apertures are formed in the metal base, however, the larger the apertures, the smaller the capacitance of the metal base is, so that the impedance increases. Thus, there is a problem that the larger the apertures, the higher the energy consumption is. If the apertures are formed in the metal base, moreover, the metal base is susceptible to an air current that is produced as the disk rotates at high speed. Thereupon, the flexure vibrates, thereby causing the problem of resonance, in some cases.
In the arrangement described in Patent Document 2, the flexure is secured to a part of the metallic carriage. While the sway of the flexure can be suppressed, according to this arrangement, electrical properties vary between a region to which the flexure is secured and other regions free from the flexure. This variation may influence signals that are transmitted in a high-frequency band, in particular, thereby hindering high-speed data transmission.